I have a 2012 Volt and need to have the coolant changed. I inquired with my dealer who sold me the car and was told that it will cost $190 to flush and refill the engine coolant, but the traction battery coolant and the electronics coolant does not need to be changed. I understand that since there is no combustion with these coolant systems and therefore no coolant contamination but I would think that the anti-corrosion chemicals blended into the Dexcool don't last forever. I don't see anything in the owners manual about changing the battery and electronics coolant but there is a schedule for the engine coolant. Is my dealer correct?